The present invention relates to a system for supplying a device with a volume of hydraulic fluid whose predetermined value varies according to operating conditions. The system includes a hydraulic jack comprising a piston and a cylinder that, together with the piston, define a variable-volume chamber connected to the device. The system also includes structure for supplying the chamber with pressurized fluid, structure for controlling the travel of the piston that may include introducing pressurized fluid into the cylinder on the side opposite the chamber, and structure for damping the movement of the piston at the end of its travel.
In general, in a supply system of the aforesaid type, the damping structure, for example, be of the hydraulic compression effect type or the servo type.
For damping by the hydraulic compression effect, the end of the jack cylinder may have a cavity designed to receive a projection of a corresponding shape provided on the piston. The jack, equipped with such damping structure, is designed for specific operating conditions. In other words, the jack is chosen as a function of the feed conditions necessary to the operation of the device. If these conditions are changed, particularly the speed of the piston at the end of its travel, the jack must be replaced by a jack whose characteristics are matched to the new conditions, which may entail assembly/disassembly operations that are often lengthy and tedious.
Servo damping by controlling the flowrate of the fluid supplied to the jack requires an apparatus comprising particular pressure and position sensors that deliver signals that are subsequently processed by a computer to regulate the fluid flowrate as the piston moves. Such apparatus is complex, expensive, and difficult to develop.